README  | 14 ++++++++++++++
 go.mod  |  3 +++
 main.go | 40 ++++++++++++++++++++++++++++++++++++++++

diff --git a/README b/README
new file mode 100644
index 0000000000000000000000000000000000000000..08ecbcd7692b61641cf64adfdb4da7e12c6ab3ba770e79d73ce66887c336c6b6
--- /dev/null
+++ b/README
@@ -0,0 +1,14 @@
+Trivial finger service for running as UCSPI-TCP server.
+
+    $ mkdir fingers
+    $ cat > fingers/@ <<EOF
+    Welcome to finger service!
+    EOF
+    $ cat fingers/user <<EOF
+    User information.
+    Bla bla bla
+    EOF
+
+    [run under daemontools'es supervise]
+    # cd fingers
+    # tcpserver -DRH -l 0 ::0 79 setuidgid user timeout 1m gofingerd 2>&1
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000000000000000000000000000000000000..fcdeff554939f2a39f1864e336b100acc00de7d6b7d7c5b40ceff9481d4f098e
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module go.stargrave.org/gofingerd
+
+go 1.19
diff --git a/main.go b/main.go
new file mode 100644
index 0000000000000000000000000000000000000000..2749f2366a90f112c322f0115523392d1f310a33c07d0f88d498ac6077bad1af
--- /dev/null
+++ b/main.go
@@ -0,0 +1,40 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"net/textproto"
+	"os"
+	"regexp"
+)
+
+func main() {
+	log.SetFlags(log.Lshortfile)
+	log.SetPrefix(fmt.Sprintf(
+		"[%s]:%s ", os.Getenv("TCPREMOTEIP"), os.Getenv("TCPREMOTEPORT"),
+	))
+	br := bufio.NewReaderSize(os.Stdin, 1<<10)
+	tr := textproto.NewReader(br)
+	q, err := tr.ReadLine()
+	if err != nil {
+		log.Fatalln(err)
+	}
+	if q == "" {
+		q = "@"
+	} else {
+		re := regexp.MustCompile("^[a-z0-9-.]+$")
+		if !re.MatchString(q) {
+			log.Fatalln("bad query")
+		}
+	}
+	fd, err := os.Open(q)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	if _, err = io.Copy(os.Stdout, fd); err != nil {
+		log.Fatalln(err)
+	}
+	log.Print(q)
+}